A. Field of the Invention
The present invention relates generally to compositions that can be used to improve the skin's visual appearance. For instance, the present invention concerns topical skin care compositions that include azuki bean navy bean or extracts thereof or a combination of both. In certain aspects, the compositions can be used to lighten skin, even out skin color, or treat hyperpigmentation.
B. Description of Related Art
Coloring in human skin is caused by melanin. Melanin is produced in special dendritic cells, melanocytes, which are found below or between the basal cells of the epidermis of the skin (U.S. Pat. No. 5,411,741). Melanin is synthesized by a reaction cascade triggered by the enzyme tyrosinase (U.S. Pat. No. 5,262,153).
Typical pigmentation is characterized by an even, uniform coloration of the skin. Many individuals have excess melanin pigmentation or a hyperpigmentation patch which can cause pigmentary variation or abnormal pigmentation of the skin. This may lead to unwanted freckles or dark spots such as senile lentigo, liver spots, melasma, brown or age spots, vitiligo, sunburn pigmentation, post-inflammatory hyperpigmentation due to abrasion, burns, wounds or dermatitis, phototoxic reaction and other similar small, fixed pigmented lesions. It is often desirable to lighten these areas or even out the appearance of irregularly pigmented areas of skin. Individuals may also wish to increase fairness or reduce the overall level of pigmentation in the skin. In either case, the hyperpigmentation is usually viewed as cosmetically undesirable and individuals often wish to lighten the skin.
There are known chemical compounds that can whiten/lighten skin. One such compound is hydroquinone. This compound, however, has been known to have skin irritating properties. Others have also attempted to create natural formulations for whitening skin. For instance, Korean Publication 10-2005-0028920 discloses the use of a rinse-off soap to wash and whitening skin. The soap includes mung beans, brown rice, adlay, white corvania (baektae) (i.e., soybean or Glycine max L. Merr.), dried Artemisia leaves, dried peach seeds, silkworms killed by white muscardine disease, sangyak, Houttuynia cordata, dried dodder seeds, orange peels, green tea leaves, sea mustard, kelp, and buckwheat. Such a composition, however, relies on a multitude of ingredients to achieve its desired effect.